indirect function calls and variable variables

[Cameron Laird]

In article <slrnbd3e45.emb.ramen at lackingtalent.com>,
Dave Benjamin  <ramen at lackingtalent.com> wrote:
>In article <vcmt074rchvb4d at corp.supernews.com>, Cameron Laird wrote:
>> PHPers do indeed use variable variables often--too much,
>> in fact.  It's a general principle that languages which
			.
			.
			.
>The reason the "variable variable" phenomenon (actually "call-by-name") pops
>up so much in PHP is due to its lack of support for functions as values.
>However, since PHP has a single, global namespace for functions, this ends
>up being an effective way to write a dispatch, and safer than an eval().
>
>> Erik illustrated the pattern with his function invocation
>> above.  He didn't write there that such usage generally
>> invites consideration for refactoring into an object-
>> oriented polymorphism scheme.
>
>I find that dispatching with an eval or dictionary lookup is often simpler
>and more concise than using subtype inheritance with polymorphism. YMMV.
>
>Dave

Yes and no.

I think people overdo polymorphism.  Dispatching with
a dictionary lookup is indeed often simpler and more
concise than inheritance elaboration.  You are quite
right.  I suspect we agree that the two are close, 
though; when a design involves one, it's probably timely
to evaluate the other, as an alternative.

I don't follow your first paragraph.  At least one of us
doesn't understand the other.  I am writing about
"variable variables", as in the variables named
  $variable1
  $variable2
    ...
one often sees in Perl and PHP code.  My observation is
that, for several reasons, it's generally better to 
transform such segments into references to
  $variable(1)
  $variable(2)
    ...
<URL: http://groups.google.com/groups?frame=left&th=4d786ca1e1b89b0c >
illustrates this.

You seem to have in mind idioms for function invocation,
rather than variable dereferencing.  Or are you making a
subtle point about one masquerading as the other?

Programmers do indeed cherish first-class functions, of
course.
-- 

Cameron Laird <Cameron at Lairds.com>
Business:  http://www.Phaseit.net
Personal:  http://phaseit.net/claird/home.html